A Little Warmth, and Seedheads on the Way??
Current
Total (March 25)
Projected Total Through March 31
Base 50 degree day (DD)
maps from the Illinois
State Water Survey. Poa seedhead predictions are overlaid
on the current and projected totals. Red represents Poa seedhead
emergence (over 100 DD). Orange represents recommended spraying
of PGRs for seedhead control (50-100 DD).
Weather
It's snowing now in Chicago, but it seems a taste
of spring may finally be coming. Models have predicted a northerly
shift in the jet stream which will allow milder air into the
region. The warmup should start on Easter Sunday and get us
to near 70 by Tuesday or Wednesday of next week! So should you
start planting those pansies or other annuals yet? If I were
a betting man, I'd definitely say no. The average last frost
date for Chicago is at the end of April, and around middle of
the month for central Illinois (see map below).
Soil temperatures are also still very low, and there isn't much
reliability in the forecast past Tuesday.
Poa seedheads
The first report of Poa seedhead emergence came
in from Carbondale today, with superintendents in the area spraying
their first application of Embark or other PGRs. The current
degree day (DD) total for that region is almost at the 100 mark
(see above map), so it is appropriate for them to start
seeing the seedheads pop.PGR timing for seedhead control can
be a very tricky business especially in the spring when unpredictable
temperature surges can make the recommended application interval
very small.
There are four methods that superintendents currently
use to time PGR applications for seedhead control. The first
and most simple method is just to apply right after the second
mowing of the turf. This is a pretty subjective practice, with
some superintendents in the Chicago area already having completed
their 1st mowing while others feel it's not even close to that
time yet. The second method is to use the Forsythia bloom as
a phenological indicator. When the Forsythia first starts to
bloom, the PGR should be applied, when the blooms are falling
off it is too late. At a recent research conference, this method
was billed as a very reliable way to time application. However,
there may be some difference in blooming by different varieties
of Forsythia or in Forsythia growing in different locations
or microclimates. The third method is to intensely scout for
Poa seedhead formation and apply at the first notice of swelling
in the boot. Others may scout by selecting a southern facing
slope of rough with Poa in it and wait for that to start seeding
first.
The fourth method, (which is used in the IT program
and is represented in the maps above), is to use base 50 degree
day (DD) accumulations as the switch. PGR applications are recommended
to commence in the 50 - 100 DD range, with 100 being the predicted
time for seedhead emergence. With next week's warmup, degree
days are projected to rise in several other areas of central
Illinois including Springfield and Decatur with the 50 DD line
being just about at Champaign and Peoria.
So which method would I choose? I would combine
all four including historical perspective (normally apply in
the first 2 weeks of April in Chicago), and other's scouting
reports. Randy and I over the last 3 years have done extensive
research on seedhead suppression, most notably with Proxy/Primo
combinations. Give us a call if you want to talk about your
plan this season or read our past research by clicking
here for the USGA TERO article or see the
Sponsored Research section of this website. Have a good
Easter weekend.
+++++++++++++++++++++++
Thanks for your support of this, as well as all
of our research programs,
Randy
Kane
CDGA
Director of Turfgrass Programs
Midwest Golf House
11855 Archer Ave
Lemont, IL 60439
630-257-8126
Lee
Miller
CDGA
Manager of Turfgrass Research
Midwest Golf House
11855 Archer Ave
Lemont, IL 60439
630-257-2005 x.106
